A hybrid-electric or all-electric vehicle includes a traction battery constructed of multiple battery cells in series and/or parallel. The traction battery provides power for vehicle propulsion and accessory features. During operation, the traction battery may be charged or discharged based on the operating conditions. Under normal circumstances, a traction battery can retain charge while the battery is resting. A traction battery that cannot effectively hold a charge while the battery is resting may cause operator dissatisfaction if the traction battery completely discharges in a short period of time.